In recent years, in wireless communication devices and the like, miniaturization and thinning of antennas have been required. Resonator antennas such as a patch antenna and a wire antenna operate when the element size thereof is equivalent to wavelength of ½ of an electromagnetic wave propagating through a medium such as a dielectric. A dispersion relationship unique to a medium exists in the relationship between the wavelength and the frequency of an electromagnetic wave, and the medium depends on the dielectric constant and the magnetic permeability in a normal insulating medium. For this reason, when an operating band and a used substrate material are determined, the size of the resonator antenna may also be determined. For example, when the wavelength in a vacuum is set to λ0, the dielectric constant of the substrate material is set to ∈r, and the magnetic permeability is set to μr, the length d of one side of the resonator antenna is expressed by the following expression.d=λ0/(2×(∈r×μr)1/2)
As is obvious from the above-mentioned expression, it is required to use a substrate material having an extremely high dielectric constant and magnetic permeability in order to drastically reduce the size of the normal resonator antenna, and thus the manufacturing costs of the resonator antenna increase.
On the other hand, in recent years, a meta-material has been proposed in which the dispersion relationship of electromagnetic waves propagating through in a structure is artificially controlled by periodically arranging conductor patterns or conductor structures. It is expected that use of a meta-material will miniaturize the resonator antenna.
For example, Patent Document 1 discloses that a meta-material is formed by a conductor plane, a conductor patch disposed parallel to the conductor plane, and a conductor via that connects the conductor patch to the conductor plane, and that an antenna is created using this meta-material.